Data storage is a critical component for computing. In a computing device, there is a storage area in the system to store data for access by the operating system and applications. In a distributed environment, additional data storage may be a separate device that the computing device has access to for regular operations. This kind of data storage is generally referred to as a primary storage, in contrast with a secondary storage, where computing devices also have access to but generally used for backing up. For data protection purposes, it is important to make regular copies of data from a primary storage to a secondary storage. While early backup strategies created complete (full) backups periodically, an alternate technique is to transfer only the incrementally modified data. By stitching together a newly modified data with a previous complete copy on the secondary storage, a new full backup can be reconstructed. This kind of backup is referred to as incremental backup.
A primary storage plays a central role in an incremental backup. The primary storage receives write requests from computing devices, and it writes data to its storage area. The primary storage also interacts with a secondary storage to transfer the incrementally modified data. The efficiency of the primary storage in data transfer is essential to improve efficiency of an incremental data backup.